1. Field of the Invention
This invention generally relates to a video recording control system, and particularly relates to a system for controlling video cameras and video recorders connected by a network.
2. Description of the Related Art
There is a monitor system including a network of cameras, displays, video recorders, and a control apparatus. It is important to previously provide the monitor system with a countermeasure for the failure of at least one of the video recorders.
The video recorders have a limited recording capacity. Accordingly, to implement endless recording, each video recorder writes a new video signal portion over an old video signal portion in a recording medium. Thus, the old video signal portion is deleted from the recording medium. It is difficult to check the contents of the old video signal portion which has already been deleted from the recording medium.
Japanese patent application publication number 11-79621/1999 discloses a monitor system for an elevator which includes a television camera, a main video recorder, a backup video recorder, a failure detector, and a switch. Normally, a video signal generated by the television camera is sent to the main video recorder via the switch before being recorded by the main video recorder. The failure detector operates to detect when the main video recorder falls into a state of failing to record the video signal. In the event that the failure detector detects the occurrence of such a failure of the main video recorder, the switch is changed by the failure detector to send the video signal to the backup video recorder rather than the main video recorder. Thus, in this case, the video signal is recorded by the backup video recorder.
The backup video recorder causes an increase in cost of the monitor system.